A double-glazing panel is a glass panel in which a space layer is formed with a spacer interposed between two glass sheets, thereby being filled with the air. Such a double-glazing panel including a space layer has an excellent heat insulating property, and therefore makes a great contribution to energy saving by being installed and used in a sash of a house or a building.
FIG. 7 is a cross-sectional view showing an essential part of a double-glazing panel 2 installed in a sash 100 as described above. In the double-glazing panel 2, a spacer 3 is interposed between two glass sheets 2a and 2b, and thereby a space layer 4 is formed therebetween. Each of glazing gaskets G made of polyvinyl chloride resin or the like is formed on the surfaces on a peripheral edge portion of this double-glazing panel 2, and the double-glazing panel 2 is installed in the sash 100 with this glazing gaskets G interposed in between. Thus, the inside of the double-glazing panel 2 is sealed to protect from rainwater and the like
As described above, a double-glazing panel is installed in a sash after glazing gaskets are attached to the surfaces of the peripheral edge part thereof. Conventionally, the glazing gaskets are attached to the double-glazing panel by manually fitting gasket members which have been molded in a channel shape in advance. However, in recent years, a manufacturing method is proposed for forming a glazing gasket by directly extruding a molding material to a peripheral edge part of a double-glazing panel by use of a molding die.
Patent Document 1 discloses means shown in FIG. 8 as a method of directly molding a glazing gasket on a peripheral edge part of a double-glazing panel.
A molding die 105 of this means is formed as a unit so that the molding die 105 would surrounds from the front side to the rear side of a double-glazing panel 2. A slide die 106 facing the front surface of the double-glazing panel 2 and a slide die 106 facing the rear surface thereof are housed in this molding die 105 having one-unit structure. The slide dies 106 and 106 are slidable in front-to-rear directions by use of cylinders 107 and 107, respectively. Glazing gaskets G and G are directly formed by extruding a fused molding material from ejection ports 106a and 106a of the slide dies 106 and 106 onto the surfaces of the double-glazing panel 2.
Meanwhile, the double-glazing panel 2 has a structure in which two glass sheets 2a and 2b are stacked with a spacer 3 interposed in between. Accordingly, parallelism between the two glass sheets 2a and 2b inevitably has an inclination more or less due to a manufacturing error. For this reason, the molding die 105 is one-unit structure surrounding from the front surface to the rear surface of the double-glazing panel 2, any one of the two slide dies 106 and 106, which are movable only in the front-to-rear directions inside of the molding die 105, cannot adhere closely to the inclined surface of the double-glazing panel 2.
The slide die 106 that cannot adhere closely thereto is separated by a gap from the surface of the double-glazing panel 2. This results in a leakage of a fused molding material from the gap or a thickness deviation, thereby deteriorating the dimensional accuracy of a glazing gasket G after molding. If the double-glazing panel 2, to which the glazing gasket G having the thus deteriorated dimensional accuracy is attached, is installed in the sash 100, it is inevitable that the sealing property of the installed portion becomes incomplete.
In addition, in the conventional method of directly molding the glazing gaskets shown in FIG. 8, the molding is carried out by setting the double-glazing panel 2 to be horizontal. Therefore, a glazing gasket molded on the upper surface of the double-glazing panel 2 and a glazing gasket molded on a lower surface thereof are apt to have different cross-sectional shapes from each other due to a difference in the influence of the gravity. This is also one of the factors deteriorating the dimensional accuracy of the glazing gaskets. Patent Document 1: Japanese Patent No. 3135841